1. Field of the Invention
The present invention relates to a process for dry surface treatment of at least one surface portion of an object, and more particularly concerns the surface treatment of polymer articles, for example to modify their wettability.
2. Description of the Related Art
With regard to the example of polymers, it is known that a polymer surface does not wet in contact with water. Instead, water forms droplets rather than a continuous film when in contact with such a surface.
Under certain circumstances or for certain applications, it is nevertheless desirable to provide polymer surfaces which can be wet with water or, in general, with a fluid (for example an ink or a paint).
The most widespread process for treating such polymer surfaces consists of the so-called "corona discharge" treatment. Such a process makes it possible to modify the wettability of a polymer surface at relatively low cost, and is already used very widely on an industrial scale.
However, there are a number of drawbacks with such a process, in particular because of the fact that it is only suitable for the treatment of thin polymer films and that it is therefore incapable of treating polymer surfaces of large articles and, in general, three-dimensional articles (in particular, the great difficulties encountered, for example, in adapting to the treatment of automobile body parts will be understood).
The Applicant Company recently proposed, in document EP-A-370870, a process for dry fluxing of a metal surface before soldering or tinning using an alloy, which is noteworthy in that the surface to be fluxed is treated, at a pressure close to atmospheric pressure, with a treatment gas atmosphere which comprises excited or unstable species and is substantially free of electrically charged species, and is obtained from a gas mixture delivered at the gas outlet of an instrument for forming excited or unstable gas species.
In this document, this process is more particularly exemplified and illustrated with the aid of a particular instrument for forming excited or unstable gas molecules, operating substantially at atmospheric pressure, which is described in the document FR-A-2,692,730 in the name of the Applicant Company.
This work has undeniably given an advantageous first response to the question of the limitation of objects which can be treated in volume.